Owing to steadily rising energy prices and increasingly stricter emission values, vehicle manufacturers are increasingly trying to reduce the energy consumption of their motor vehicles, in particular the energy consumption which is not directly used to drive the motor vehicle. This includes in particular energy consumption while idling as well as the energy consumption of various electrical consumers within the motor vehicle.
The present invention is concerned with the problem of creating a cooling system in a motor vehicle, which has a much lower energy requirement compared to previously known cooling systems.
This problem is solved according to the invention by the subject matter of the independent claim 1. Advantageous embodiments form the subject matter of the dependent claims.
The present invention is based on the general idea of, in a cooling system with a cooling circuit in which at least one consumer to be cooled, for example an internal combustion engine, one pump and one cooling device are arranged, connecting a pressure side and an intake side of the pump by means of a short circuit line, that is, by means of a bypass line, which is opened when cooling is not necessary and thereby conducts at least most of a coolant flow no longer through the internal combustion engine and the whole cooling circuit but diverts it into a short circuit with much less resistance. In order to divert or divide the coolant flow to the internal combustion engine or to the short circuit line which bypasses the pump, a valve device is used, which requires much reduced actuation forces owing to the short circuit line which is now present and thereby can be configured to be smaller and also more economical with regard to energy consumption. The valve device according to the invention is arranged in the region of the short circuit line, for example in the region of a branch of the short circuit line from the cooling circuit or in the region of a junction of the short circuit line into the cooling circuit. Furthermore, the valve device according to the invention can be switched between at least two positions, wherein in the first position at least most of the coolant flow flows through the short circuit line and in the second position at least most of the coolant flow flows through the internal combustion engine and not through the short circuit line. Any desired intermediate positions which allow any desired division of the coolant flow between the actual cooling circuit and the short circuit are of course also conceivable. If for example no cooling effect is needed in the internal combustion engine or another consumer to be cooled, the valve device can be moved into its first position and thereby the cooling medium can be pumped through the short circuit with comparatively low resistance. With the valve device according to the invention which is arranged in the region of the short circuit line, it is thus possible to control the cooling demand in the internal combustion engine and thus also the output of the coolant pump in a relatively flexible manner. If the internal combustion engine does not need cooling, the valve device is then simply moved into its first position so that at least most of the coolant flow flows through the short circuit line and no longer through the internal combustion engine or the cooling device.